Function: After the inter-cell welding is completed, the quality of the welding spot is detected, the principle is to give five welding spots through a constant current, and at the same time, the voltage at both ends of the welding spot is detected by millivolt voltmeter.  if which is bigger, a voltmeter readings that corresponds to the welding spot resistance is big, too much resistance value shows that the welding quality is bad, exceed the set value, the machine will alarm.